Secrets of the Lost Quest - Help

[Under Your Bed]

In game I'm told to go to the steps of torment to find a tome. Where's the 4th floor?

I tried using that map hack link with the detailed map, but I don't understand how to use it so still can't find any 4th floor.

I got to the end, killed some boss then just exit the area. No tome. Really stuck with this quest.

Is there a console command to give my char the tome or just complete the quest?

[Zadown]

Sounds like you didn't go through the locked door into the actual proper Steps of Torment dungeon. You need a Skeleton Key for that, which you can either craft or get from a quest.